ODR merging and implicit typedefs

[Eric Botcazou]

> I bootstrapped/regtested on x86_64-linux the patch bellow. If it will work
> for Firefox and Chrome I will go ahead with it at least temporarily.

Really?  This introduced a LTO failure in the gnat.dg testsuite:

FAIL: gnat.dg/lto8.adb (internal compiler error)
FAIL: gnat.dg/lto8.adb (test for excess errors)
WARNING: gnat.dg/lto8.adb compilation failed to produce executable

lto1: internal compiler error: in odr_types_equivalent_p, at ipa-devirt.c:1276
0x86a263 odr_types_equivalent_p
	/home/eric/svn/gcc/gcc/ipa-devirt.c:1276
0x86bf44 odr_types_equivalent_p(tree_node*, tree_node*)
	/home/eric/svn/gcc/gcc/ipa-devirt.c:1718
0x5c563a warn_type_compatibility_p
	/home/eric/svn/gcc/gcc/lto/lto-symtab.c:219
0x5c6103 lto_symtab_merge
	/home/eric/svn/gcc/gcc/lto/lto-symtab.c:336
0x5c6103 lto_symtab_merge_decls_2
	/home/eric/svn/gcc/gcc/lto/lto-symtab.c:520
0x5c6103 lto_symtab_merge_decls_1
	/home/eric/svn/gcc/gcc/lto/lto-symtab.c:671
0x5c6103 lto_symtab_merge_decls()
	/home/eric/svn/gcc/gcc/lto/lto-symtab.c:694
0x5bb9cc read_cgraph_and_symbols
	/home/eric/svn/gcc/gcc/lto/lto.c:2891
0x5bb9cc lto_main()
	/home/eric/svn/gcc/gcc/lto/lto.c:3277

-- 
Eric Botcazou